Window roller shutters (hereafter: roller shutters) are usually rolled up on a shaft at the top of the window from which they are unrolled until the adjacent, horizontally arranged slats form a mainly vertical cover. In order to allow the roller shutter to be rolled up on the shaft, the slats are connected each to their adjacent slats in an articulated manner such that they can perform a relative pivoting motion about an axis arranged parallel to the longitudinal axis of the slats.
In order to ensure a reliable, reproducible motion of the roller shutter or slats while operating the roller shutter between the rolled-up rest position on the shaft and the rolled-out covering position, it is typically the case that the slat end faces are inserted into lateral guide rails and can slide along these guide rails.
Architecture may include so-called upright-less window corners in which the glass panes meet at an angle of e.g. 90° and are bonded directly to each other, in particular with an adhesive, without the use of an additional corner upright. When attempting to cover both windows with roller shutters, the problem arises that one either has to install a guide rail immediately in front of the corner formed by the glass panes (which is not aesthetically pleasing) or has to do without a guide rail for the roller shutters in this area, which makes the roller shutters unstable and renders operation of said roller shutters unreliable. Roller Shutters are therefore not usually used in this case. Instead, alternate solutions are employed that are less ideal than roller shutters in terms of thermal insulation, sound-proofing, and burglary protection.